Gunmen and security forces linked to Syria’s new Islamist rulers have killed more than 340 people, including women and children from the Alawite minority, in the country’s coastal region since Thursday, the head of a war monitor said.

Reuters could not independently verify the reports.

Rami Abdulrahman of the Syrian Observatory for Human Rights said the widespread killings in Jableh, Baniyas and surrounding areas in Syria’s Alawite heartland amounted to the worst violence for years in a 13-year-old civil conflict.

The new ruling authority on Thursday began a crackdown on what it said was a nascent insurgency after deadly ambushes by militants linked to former president Bashar al-Assad's government.

Several dozen members of the security forces have been killed in heavy clashes with militants, a Syrian security official said.

Officials have acknowledged violations during the operation, which they have blamed on unorganized masses of civilians and fighters who sought to support official security forces or commit crimes amid the chaos of the fighting.

A defence ministry source on Saturday told state media that all roads leading to the coast had been blocked to stop violations and help return calm, with security forces deploying in streets of coastal cities.

The source added that an emergency committee set up to monitor violations would refer anyone found not to have obeyed the orders of the military command to a military court.

The reported scale of the violence, which includes reports of an execution-style killing of dozens of Alawite men in one village, puts into further question the Islamist ruling authority's ability to govern in an inclusive manner, which Western and Arab capitals have said is a key concern.

Assad was overthrown last December after decades of dynastic rule by his family marked by severe repression and a devastating civil war.

Syria’s interim president, Ahmed Sharaa, while backing the crackdown in a televised address late on Friday, said security forces should not allow anyone to “exaggerate in their response... because what differentiates us from our enemy is our commitment to our values.”

“When we give up on our morals, us and our enemy end up on the same side,” he said, adding that civilians and captives should not be mistreated.

Family and Friends in Mourning

Syrian Facebook on Saturday was filled with images and obituaries of people from the coastal area being mourned by family and friends who said they had been killed.

Abdulrahman, a leading critical voice against the Assad-led government who documented its alleged killings for more than a decade, said: “This is not about being pro or against the former Assad regime. These are sectarian massacres that aim to expel the Alawite population from their homes.”

The defence ministry and internal security agency said on Saturday they were trying to restore calm and order and prevent any violations against civilians in the coastal region.

Six residents of the coastal region said thousands of Alawites and Christians had fled their homes since Thursday, fearing for their lives.

Several hundred, mostly women and children and elders, sought refuge at a Russian Mediterranean military base at Hmeimim in Latakia, according to footage from the scene and two people familiar with the matter.

Abdulrahman and four people in the coastal region who spoke on condition of anonymity said killings, looting and burning of homes had continued overnight in Baniyas and in surrounding villages.

Reuters could not independently verify the assertions.